There are cases in which provision of a water proof function is required in portable electronic devices (for example, mobile phones). In order to give the waterproof function to the electronic devices, it is desirable to prevent exposure of charging terminals and it is necessary to adopt a method of transferring power in a contactless manner for charge without the provision of the charging terminals. Battery packs including dielectric coils have been developed in recent years in order to transfer power in a contactless manner for charge. PTL 1 discloses a battery pack including a secondary battery and a flat-shaped coil. In the battery pack in PTL 1, the flat-shaped coil is deposited on one face (a first flat face), among two opposing faces of the secondary battery having a width larger than its thickness, via a sheeted electromagnetic shielding film.
PTL 2 discloses a battery pack including a secondary battery and a flat-shaped coil. In the battery pack in PTL 2, the flat-shaped coil sandwiched between a radio wave absorbing layer and a laminating layer is deposited on one face (a flat face), among two opposing faces of the secondary battery having a width larger than its thickness.
PTL 1: Japanese Unexamined Patent Application Publication No. 2008-66140
PTL 2: Japanese Unexamined Patent Application Publication No. 2008-48482